Studies on late deterioration of renal grafts will be continued with the specific aim of detecting immune complexes composed of transplantation antigens and antibodies in the circulation of the recipients and deposits of such complexes in the renal grafts. Further studies on human immune complex nephritides will be conducted in order to ascertain the role of tissue antigens in these maladies. Skin reactive transplantation antibodies will be further studied in rat, and major attempts will be made to detect such antibodies in other species, first of all, in man. Kinetics of formation of humoral transplantation antibodies in rat recipients of renal allografts will be further investigated. The effect of immune responses to transplantation antigens on the course of pregnancy and fetal mortality will be investigated. Proliferative responses of lymphocytes will be further investigated with the major emphasis on definition of stimulators which do not require cell cooperation. BIBLIOGRAPHIC REFERENCES: Kondracki, E. and Milgrom, F.: Lymphocyte Stimulation in Agarose-Gel Cultures by Mitogens. Fed. Proc. 35: 511, 1976 (Abstract). Mori, S., Kano, K and Milgrom, F.: Humoral Antibody Responses in Rat Renal Allotransplantation. Fed. Proc. 35: 649, 1976 (Abstract).